This invention relates to an apparatus and method of operating a steam generator tube bank and, more particularly, to such an apparatus and method in which debris and deposits are removed from the tube bank by inducing vibration of the tubes of the tube bank.
Steam generator tube banks are well known in the art. Particularly in a fluidized bed reactors a hot, particulate-containing gas stream is passed across such steam generator tube banks to heat a cooling fluid flowing through the tubes. The main purpose of the tube bank is to provide for heat transfer to the cooling fluid, however, as a result of their location, these tube banks act to remove a portion of the particulate material from the gas stream as a portion of the particulate material strikes the tubes and adheres thereto or falls out of the gas stream.
Steam generator tube banks typically include a steam drum, a plurality of tubes extending downwardly from the steam drum to form a tube bank, and a water or "mud" drum located below the steam drum and receiving the cooling fluid from the tube bank. From the water drum, the cooling fluid is then returned to the steam drum or circulated to other portions of the fluid flow circuitry of the reactor for further heat transfer to the cooling fluid.
Such steam generator tube banks provide advantages such as increasing heat transfer from flue gases and decreasing the amount of particulate material in such flue gases. However, such steam generator tube banks are not without problems. For example, as particulate material adheres to the surfaces of the tubes, the heat transfer to the cooling fluid decreases. Excessive buildup may also impede gas flow and increase the pressure drop across the tube bank.
In other applications, mechanical rappers have proven to be effective in removing deposits from tubes. However, the bulk, mass, and rigidity of the steam drum and the water drum make rapping ineffective as a means for cleaning such steam generator tube banks. Accordingly, these deposits are typically removed using a sootblower or other less desirable method.